To meet the demand for wireless data traffic having increased since deployment of 4th generation (4G) communication systems, efforts have been made to develop an improved 5th generation (5G) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post LTE System’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like.
In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
There recently has been ongoing research for introducing a communication technology in a super-high frequency band of 30 Ghz or higher, that is, a millimeter wave system, as a scheme for providing a high data transmission rate. In the millimeter wave system, a serious propagation path loss occurs and significantly decreases the cell coverage. Therefore, in order to solve the problem of propagation path loss in the millimeter wave system, there has been active research for applying a beamforming technique, which improves the transmission/reception efficiency of an antenna by concentrating transmission/reception power in a narrow space.
Generally, in a communication system supporting beamforming, a mobile station and base station have to perform a beamforming training process for finding an optimal uplink transmission/reception beam and downlink transmission/reception beam, respectively. To this end, 802.11ad standards have various beamforming protocols defined with respect to beam training schemes for finding optimum beams, but specific schemes for applying various beamforming protocols have not yet been presented.